Privia PX-350M Line out signal is too noisy

[construer]

Hi, 

 

I was searching the web to figure this out and couldn't find anything useful. While my PX-350M works great for playing, when I connect it to my comp I get noisy signal. 

 

At first, I connected it to my old Delta 1010LT via generic unbalanced cable, since 1010lt has unbalanced inputs only. So I thought it might be the problem. 

 

Then, I bought Focusrite Scarlett audio interface, plugged it in my new laptop, and connected PX-350M using balanced American Audio cable. Nothing changed. 

 

In both cases I have to gain signal A LOT to get some sound at all. So I thought some settings are issue. I turned up all volume settings I could find in PX-350M. Still the same. 

 

And then, I made audio recording, saved it to USB and signal is still too low/noisy-when-gained. 

 

As it is now, it is impossible to make any, at least somewhat, professional recording with it.

 

Any help, advices, links... will be really appreciated. 

 

Thanks, 

Marko

[Brad Saucier]

Is USB MIDI connected to the PX-350?  Have you tried the headphone output to your audio interface?

[construer]

Thank you for your reply and good will. 

 

I tried different variations. With USB MIDI connected or disconnected. Tried headphone output, it gives the same buzzy noise. 

 

When cables are disconnected from audio interface and I turn gain on interface to maximum, it gives some hissing noise. When I plug in cables only in interface, but not in PX-350m, there is no noise added. When I plug in cables into PX-350m, buzzing starts immediately and is prominent even on lower gain levels on interface. It is the same sounding buzz that comes out of headphone output and that is recorded to USB flash. I tried recording to USB with cables connected or disconnected. Same. 

 

However, on PX-350m speakers sound is clean. There is no buzz even on max volume. 

[Jokeyman123]

One more possibility if you haven't tried it-page 8 in the manual states that you need to put a stereo headphone plug in the headphone jack when connecting/using the line outs-to improve the sound quality-this must change the line out impedance to match a recording device or amp. Strange function, but if you haven't tried that it might solve the problem. 

[Brad Saucier]

Can you upload a WAV file you recorded to the USB flash drive using the PX-350 completely stand alone? ...no cables connected to it other than the main power adapter.  Also do not edit the WAV file. 

[construer]

This headphones thing solved the problem. I was preparing to record all possible variations, and connected headphones (while line out cables were connected) just to check if the buzz is there too. Sound was perfect. As was via line out/audio interface after that. Even after headphones were detached. 

 

Thank you both for replying.  

 

Note to myself: don't treat "important" as a footnote in the manual. 🙂

 

Thanks

[Jokeyman123]

Great! Thought I remembered having to do this with my PX350. Not exactly a logical or intuitive way to go-may be designed this way so you can monitor your paling/recording-in an indirect way-with your computer-in case your recording device can not do this-does not have stereo headphone jacks out-which is odd since almost every computer and digital or analog recorder allows for  a stereo headphone out jack to monitor ypour playing/recording. Threw me for a loop too at first. Glad we solved your problem-and yes important could very well be important, unless it isn't (Yogi Berra might have said this). 

[construer]

FurElise - Reharmonized.mp3

 

This is the sound I got in the end. After some compression, this buzz and noise is still there, but I think PX350 sounds great. It would be nice to get rid of noise completely though, if possible, so if you (or anybody) have any further tip to do that it would be great and appreciated. If not, I'm grateful for this sound as is. 

 

Thanks

[Brad Saucier]

What was your setup to record that?  

[construer]

My home recording setup is PX-350m -> Balanced Cables -> Focusrite Scarlet 2i2 -> Asus Laptop

 

I did some experimenting with connecting and disconnecting various cables with the line in gains and headphones output on Focusrite turned to max. In recording I've posted, the buzz came from the USB cable I used to connect keyboard with PC. I guess it was masked at first with much bigger buzz of not having headphones plugged into PX-350. I'm not sure if it is because the cable is too old. I'll try new one. I made new recording with this cable detached and recording was clear. Also MIDI Out DIN cable caused some buzz, but not MIDI In. And also, the length of (unbalanced) cable connected to Headphones output on piano made the difference.

 

So eventually, for recording I will use: Headphones and Line Out connected, USB cable and MIDI Out cable disconnected.

 

I'm posting an MP3 with the new (shorter) recording followed by the old recording. I believe the sound is clear. 

 

Question for Brad: your first question was about USB Midi cable and now I wonder is this known issue? I did intend to use piano to play MIDI through it and capture audio, and if a new cable doesn't solve it, I'll have to find workaround. 

 

However, I consider this buzz issue solved and thank you both for helping me out. 

FurElise - Reharmonized - Comparison.mp3

[Jokeyman123]

What computer is all this going into? Hardware quality for sound recording and USB data throughput is not consistent from computer to computer. Laptops are terrible for shielding interference from the motherboard and other ports-just stick an old AM radio next to a laptop when you turn it on and listen to what is coming out of a laptop (or desktop) as far as RFI interference. and typical USB cables do not have much shielding and audio cables may not be much better.  This may be why longer cables were worse-becomes an antenna for radio interference from your computer. And even a slight bit of a loose connection anywhere can cause all kinds of hum and interference problems. 

 

Keep in mind that the USB 2.0 spec for anything is rather low, thus the push for USB 3.0 although if the computer internal hardware isn't up to it, USB throughput speed will only increase the problems for recording audio or passing a midi data stream, even with the best usb audio interface and/or usb cables. This is why the original midi spec through DIN ports was so thorough-with optoisolators required for hardware for all connections to avoid these problems. USB specs have no such requirements.

[Brad Saucier]

USB in general is known to cause a ground loop in analog audio on many devices.  It is a common problem because the worldwide USB standard was never designed to handle this. Search the internet for "usb ground loop noise" and you'll find many different stories about it and solutions.  The DIN MIDI standard was designed with noise in mind, as it has noise isolation built in.  I'm not sure why your DIN output would be causing any noise at all, since this connection is so good at isolating noise.  As far as the line outputs on the PX, they are unbalanced outputs, not balanced.  I'm not sure that would make any difference, but you may want to switch to unbalanced cables. 

 

Tip for best sound, disconnect everything except the PX-350 power supply and record directly to the built in audio recorder.  

[construer]

Ok, now I feel stupid. I've read somewhere and been convinced that line outs on PX350 are balanced. 

 

I did what Brad said - no cables attached, and sound is great too. Since recording to USB flash was my first choice, I'm now confused. For sure, some cables were connected (can't remember which ones), USB midi wasn't, but the sound was awful. Half of a signal was the noise. I can't find that first takes to post them.

 

Now, even when I record to USB flash with headphones and MIDI in connected (those two I need) sound is still great.

 

My home recording setup is very low budget and I hoped to achieve semi-professional recording level. But now, sound quality is way better than I hoped for. 

 

Thanks so much!